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BIG PHYSICS, BIG QUESTIONS –

Europe lets in American supermaize …

By Debora MacKenzie

Brussels

THE European Commission has finally decided to allow a controversial
genetically modified maize into Europe.

The British government, which originally challenged approval for sale of the
maize in Europe, says it is happy with the decision, now that the Commission has
consulted with its scientific advisers. But Tony Atkinson, the scientist who
persuaded Britain to oppose the crop, is still highly critical of the move. And
the Austrian government has lodged a legal challenge to the decision.

The maize, produced by the Swiss-based company Ciba-Geigy and grown in the
US, contains a gene which makes the plant resistant to a herbicide, glufosinate,
and a gene from the bacterium Bacillus thuringiensis which produces Bt,
an insecticide.

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France approved the maize for sale in the European Union a year ago, but in
April Britain blocked the move (This Week, 4 May 1996, p 7). The dispute was
referred to three scientific committees that advise the Commission on animal
nutrition, food and pesticides. In December, the committees decided that the
maize was safe to market. But their reports have not been published.

The British Advisory Committee on Novel Foods and Processes (ACNFP) was
worried about a third gene in the maize, for an enzyme called beta-lactamase.
The enzyme destroys ampicillin, an antibiotic in the penicillin family. Ciba
scientists used the gene to help determine whether plants had been genetically
modified or not.

But Tony Atkinson of the drugs company Duramed, an ACNFP member, still fears
that the beta-lactamase gene will jump from corn to bacteria in an animal’s
intestine. “No one has yet looked at the effect of feeding a gene to lots of
animals day in and day out for years,” he says.

Ciba argues that up to 10 per cent of human gut bacteria already contain the
beta-lactamase gene, and that there are other antibiotics which are not
destroyed by the enzyme. But Atkinson notes that the gene in the new maize is
coupled with a stretch of DNA which causes cells to make 600 copies of the
gene.

This will not only make it more likely that a gene will eventually jump from
maize to bacteria. It will also mean that once it does jump, the bacteria might
produce the enzyme in large enough quantities to destroy a wide range of
beta-lactam antibiotics. “The argument that there are plenty of antibiotics that
will still work even if this particular gene spreads makes me squeamish,” says
Tony Medeiros of the Miriam Hospital in Providence, Rhode Island, an expert on
antibiotics.

Atkinson points out that the US company Monsanto has applied to market a
Bt-producing maize in Europe that does not contain the beta-lactamase gene. John
Beringer of the University of Bristol, head of Britain’s Advisory Committee on
Releases to the Environment, believes the risk from the gene is low. But he adds
that he is “staggered” that Ciba did not avoid the controversy by removing the
beta-lactamase gene from the maize before applying to market it.